What is the reason for slag hanging after cutting by laser cutting machine

Laser cutting machine is widely used in daily life, ranging from electric vehicles to pots and pans. Compared with traditional cutting methods, laser cutting machine is faster and more accurate. Its working principle is to use high-energy laser beam to heat the target area and melt it to achieve the purpose of cutting. During cutting, there may be slag hanging on the workpiece. What is the reason? Let's take a look.

laser cutting


What is the reason for slag hanging after cutting by laser cutting machine?


We call the residual metal melt on the cutting back of those workpieces as hanging slag. Laser cutting machine will produce a lot of heat during processing. Generally speaking, the heat generated during cutting will spread to the whole workpiece along the cutting seam, and then the workpiece will be fully cooled.


However, when cutting small hole workpieces, the outside of the hole can be fully cooled, and the inside of the hole can cause excessive slag hanging due to small heat diffusion space and excessive heat concentration.


In addition, when cutting thick plates, the molten metal accumulated on the material surface during perforation and heat accumulation will disorder the auxiliary air flow and input too much heat, resulting in slag hanging.


How to solve it?


After slag hanging occurs in cutting, first find out the causes from the following points, and then adjust them to solve the generation of slag hanging.


1. Laser output power

When cutting thick plates, the power is not enough to melt the whole plate. If the power can be adjusted, increase the power and continue to test whether it can be cut off. If the power has been adjusted to the maximum, it is necessary to replace the laser with a higher power.


2. Deviation of laser beam focus

Too close or too far focus will affect the cutting quality. It can only be adjusted through inspection and according to the offset position.


3. The air pressure of auxiliary gas is not enough

The auxiliary gas can blow away the slag during cutting and cool the cutting heat affected zone. If the air pressure is too small, the residue will not be blown out of the workpiece or the workpiece will not be cooled in time, resulting in the formation of slag hanging. Adjusting the air pressure to an appropriate value.


4. Cutting speed is too fast or too slow

If the feeding speed of laser cutting is too fast, the workpiece cannot be cut in time, oblique lines will be formed on the cutting surface, and slag will hang in the lower half area. If the feed speed is too slow, there will be over melting, the overall section is rough, the cutting seam becomes wider, and there will be slag hanging in the upper half.

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